Magnet system having a center pivoted armature



H. SAUER April 12, 1966 MAGNET SYSTEM HAVING A CENTER PIVOTED ARMATURE 2 Sheets-Sheet 1 Filed March 11, 1964 April 12, 1966 H. SAUER 3,246,211

MAGNET SYSTEM HAVING A CENTER PIVOTED ARMATURE Filed March 11, 1964 2 Sheets-Sheet 2 wwz United States Patent Claims. (Cl. 317-197 This invention relates to magnet systems, and more particularly to an electromagnetic system including a movable armature.

The term magnet system as employed hereinafter will be understood to refer to an arrangement which includes a coil of conductive material and a magnetic or iron circuit which provides a path for the magnetic flux generated by the coil' when energized by electric current, the path being closed except for one or more air gaps, and being as short as possible. The magnetic circuit of a conventional magnet system normally consists of a core in the coil, a yoke, and a movably arranged armature. The efficiency of the magnet system is determined to a large extent by the dimensions of the coil, the effective cross section of the iron circuit, the width of the air gaps, the shape of the flux path, and also by the position and number of the air gaps. Design variables may be calculated to give favorable values to the several factors.

It is a primary object of the invention to provide a magnet system in which the several factors enumerated above are coordinated in a favorable manner regardless of design details.

Another object of the invention is a magnet system in which the armature is protected from mechanical shock and vibration.

An additional object is the provision of a magnet system whose weight and bulk is small as compared with conventional systems of equal effect.

Yet another object is a magnet system in which the inertia of the armature does not significantly affect the functioning of the system.

A further object is the provision of a magnet system which is not affected by relatively large tolerances in the manufacture of the individual parts thereof, and in the assembly of the individual parts.

With these and other objects in view, the invention, in one of its aspects provides a stationary coil. A portion of a mounting member is received in a cavity of the coil. An armature is mounted on this mounting member portion for pivotal movement about an axis which passes as closely as possible through the center of gravity of the armature. The mounting member is abuttingly interposed between two pieces of ferromagnetic material secured on the support to hold the pieces at a fixed distance from each other transversely of the pivoting axis of the armature. The terminal armature portion is arranged between the pieces.

The exact nature of this invention as well as other objects and advantages thereof will be readily apparent from consideration of the following specification relating to the annexed drawing in which:

FIG. 1 shows a first electromagnetic relay embodying the magnet system of the invention in a fragmentary perspective view; and

FIG. 2 illustrates another relay including the magnet system of the invention in a fragmentary perspective view.

Referring first to FIG. 1, there is seen a base plate 18 on which the other elements of the relay are mounted. A housing 2 is connected to the base plate 'by four integral legs 2. A bottom plate 11 downwardly closes the housing 2. A solenoid coil of which only a few turns 1' 3,246,211 Patented Apr. 12, 1966 on the form 1 are shown in the drawing for the sake of clarity, is mounted in the housing 2 by means of screws 3. The screws pass through smooth bores in the top of the housing and engage threaded bores at opposite ends of a flat upper mounting bar 8. A lower mounting bar 8' is arranged at the bottom of the passage in the form 1, and is fastened to the bottom plate 1 1 by screws, not visible in the drawing, in the manner of the screws 3.

The mounting bars 8, 8 pass through the axial cavity of the solenoid form 1. The form has two flanges which are axially held between the screws 3. Integral reinforcing bosses 6 on the flanges adjacent the screws 3 abut against the ends of the mounting bar 8 and absorb the clamping stress of the screws 3. Similar bosses, not visible in the drawing are interposed between the lower mounting bar 8' and the bottom plate 11. The bosses abut from above and from below against two pole pieces 10 of permanently magnetic material, and thereby fixedly define the vertical position of the pole pieces. The terminal portions of the mounting bars 8, 8 are abuttingly interposed between the two pole pieces 10, and the two leg portions of a U-shaped yoke 7 which are integral portions of the housing 2 laterally hold the pole pieces 10 in abutting engagement with the mounting bars 8, 8.

A pivot pin 5 having two end portions of reduced diameter connects the mounting bars 8, 8 in the center of the passage through the solenoid form 1. The shoulders 4 of the pin 5 center the pin 5 between the mounting bars. The pin carries an armature 9 which projects outward of the passage in the solenoid coil form 1 into the space be tween the two pole pieces 10. Pivotal movement of the armature about the axis of the pin 5 moves the terminal armature portion seen in FIG. 1 toward and away from the pole pieces. The armature 9 is spaced from the bars 8, 8' and freely movable with the pin 5 whose axis passes through the center of gravity of the armature. In the central position of the armature illustrated in FIG. 1, it defines with the two pole pieces 10 two air gaps of equal width L/2.

The magnetic circuits of the permanently magnetic pole pieces 10 are indicated by broken lines F. One circuit extends from the air gaps through the pole pieces and in a closed path upward through the yokes 7 and other elements of the housing 2. Another circuit is closed through the bottom plate. 11. A third circuit includes two legs 2' and the base plate 18. g

It will be understood that the open end of the housing 2 which faces away from the viewer in FIG. 1 carries two additional pole pieces in the same manner as the pole pieces 10 visible in FIG. 1, and that the other terminal portion of the armature 9 is arranged between the two non-illustrated pole pieces to define two additional air gaps. The magnetic elements of the relay thus are symmetrical with respect to a plane perpendicular to the axis of the coil.

A rod 12 depending from the visible terminal portion of the armature 9 carries an insulating bead or button 15 which urges a movable contact spring 13 against one or the other of two fixed contacts 14 when the armature 9 is attracted toward one or the other of the two pole pieces 10. The folded contact spring 13, is mounted on terminal pins 16 which are supported in the base plate 18 in tubular glass insulators 17 prepared by fusing glass to the base plate and to the pins. Five pins are seen in the drawing. Two of the pins are the terminals of the solenoid coil whose windings are not otherwise shown in order not to crowd the drawing. Obviously the same contact arrangement can be provided symmetrically on the opposite of the relay.

The structure shown in FIG. 1 constitute a sensitive polarized relay the operation of which is too obvious to require explicit description. It will be understood that the invention is not limited to polarized relays, and that the structure shown may be modified to constitute a nonpolarized relay without departing from the scope of this invention. The modification involves no more than a replacement of the permanently magnetic material of the pole pieces by yokes in the manner of the yokes 7, whereas the two non-illustrated pole pieces are omitted or replaced by pieces of diamagnetic material.

The relay illustrated in FIG. 2 is enclosed and supported in an iron housing 38 which is a U-channel of substantially uniform cross section. The top ofthe channel is closed by a cover plate 24 which is normally attached to the housing 38 in a conventional manner, not illustrated.

Only one terminal flange 23 of the solenoid coil of the relay is visible in FIG. 2. Lugs 22, 39 at the top and bottom of the flange 23 respectively engage a recess 21 in the cover plate 24 and a groove 40 in the bottom of the housing 38. Two pole pieces 33 of permanently magnetic material are vertically secured between paired studs 32, 32' in the vertical walls of the housing 38. They are held apart and in abutting engagement with the vertical housing walls by two flat mounting bars 26 of which only the upper one is visible in FIG. 2 A transverse strap 27 attached to the top of the upper mounting bar 26 extends over the top face of the magnetic pole pieces 33 and the bar 26 is thereby held against the solenoid form. The non-illustrated mounting bar will be understood to be equipped with a transverse strap which abuts from below against the pole pieces 33.

The structure so far described is duplicated at the other end of the housing 38 not visible in FIG. 2.

Two lugs 29 integral with the cover plate 24 are bent downwardly from the generally horizontal plane of the plate 24. They abut from opposite sides against the free ends of a leaf spring 25 which is bent into an approximate inverted W-shape. The central portion of the spring 25 is fastened by a screw 28 to the terminal portion of an armature 31 which is arranged between the two pole pieces 33. The screw also fastens a U-shaped resilient separator strip 30 to the terminal armature portion. The movable free end of a contact spring 34 carries a stud 37 of insulating material under the resilience of the strip 30, and is shown centered between two fixed contacts 35, 36 by the leaf spring 25. The contacts 35, 36 are mounted in the bottom of the housing 38 in glass insulators 41. The similar mounting of the contact spring 34 is not visible in the drawing.

The armature 31 is pivotally mounted between the two mounting bars 26 in a manner analogous to the mounting of the armature 9 between the mounting bar 8, 8' in FIG.

, 1. When the coil of the solenoid is energized, the terminal portion of the armature 31 carrying the strip 30 moves toward one or the other of the pole pieces 33 depending on the direction of current flow if the current is sufficient to overcome the force of the spring 25. Upon interruption of the energizing current, the spring 34 returns to its illustrated position, and the circuit between the contact spring 34 and one of the fixed contacts 35, 36 is opened. The tension of the spring 34 is adjustable by bending the lugs 29 in either direction. Depending upon that adjustment the deenergized armature has its normal position on either side of the pole pieces 33 or central as demonstrated.

The strip 30 is preferably made of diamagnetic material to prevent sticking of the relay. If the strip 30 is made of steel, the holding force of the armature 31 is increased.

The relay illustrated in FIG. 2 provides two paths of permanent magnetic flux on each end of the armature 33, only one end being shown in the drawing. The paths, indicated by broken lines F, extend from the two pole pieces 33 and the vertical housing walls. They are completed by the cover plate 24 and the bottom portion of the housing 38 respectively. The cover plate 24 is preferably fastened to the housing 38 by spot welding.

The response of the illustrated relay may be varied in a simple manner by bending the lugs 29 toward or away from the leaf spring 25.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims.

What I claim is:

1. A magnet system comprising, in combination:

(a) a coil having an axis and being formed with a cavity therein;

(b) an armature member having a center of gravity,

a portion of said armature member being mounted in said cavity for movement about a pivot axis transverse of the axis of said coil and passing through said center of gravity, and a terminal portion of said armature member projecting outward from said cavity;

(c) substantially U-shaped magnetic yoke means; and

(d) two pole pieces on said yoke means oppositely spaced from the axis of said coil in a symmetrical arrangement relative to said last-mentioned axis, said terminal portion being arranged between said pole pieces for movement about said pivot axis between two positions respectively closely adjacent said pole pieces.

2. A system as set forth in claim 1, further comprising a mounting member having a portion secured in said cavity and movably supporting said armature member, another portion of said mounting member being abuttingly interposed between said pole pieces for holding the same at a predetermined distance from each other transversely of the axis of said coil.

3. A system as set forth in claim 2, wherein said pole pieces project from said yoke means toward each other and toward the axis of said coil.

4. A system as set forth in claim 1, further comprising a support, said coil and said yoke means being mounted on said support, a portion of said support constituting a magnetic circuit with said pole pieces and said terminal portion of the armature member, an air gap being interposed between at least one of said pole pieces and said terminal portion.

5. A system as set forth in claim 4, said magnetic circuit including at least one permanent magnet.

6. A system as set forth in claim 1, wherein said pole pieces are permanently magnetic.

7. A system as set forth in claim 1, further comprising switch means operatively connected to said armature for operation thereby.

8. A system as set forth in claim 7, further comprising a support, said coil, said yoke means, and said switch means being mounted on said support, the switch means j on said support for resiliently controlling the response of said armature member to the energizing of said coil.

10. A magnet system comprising, in combination: (a) a support; (b) a coil fixedly mounted on said support, said coil having an axis and being formed with an axial passage therethrough;

(c) a mounting member, a portion of said mounting pieces to hold said members at a fixed distance from member being received in said passage; each other transversely of said axes, and the terminal (d) an elongated armature member having a center of portions of said armature being respectively arranged gravity, said armature member being mounted on said between the pole pieces of said pairs. portion of said mounting member for pivotal move- 5 ment about a pivoting axis transverse of the axis of References Cited y the Examiner said coil, said pivoting axis substantially passing UNITED STATES PATENTS through the center of gravity of said armature member, and two terminal portions of said armature mem- 2863103 12/1958 Tancred 317 197 2 916 584 12/1959 Molyneux. her being spaced from said pivoting axis In opposite 1 directions; and 1 3,030,469 4/1962 Lazich.

(e) two pairs of pole pieces secured on said support,

said mounting member being abuttingly interposed BERNARD GILHEANY Pr'mary Exammer between the members of each pair of said pole GEORGE HARRIS, 1a., Assistant Examiner. 

1. A MAGNET SYSTEM COMPRISING, IN COMBINATION: (A) A COIL HAVING AN AXIS AND BEING FORMED WITH A CAVITY THEREIN; (B) AN ARMATURE MEMBER HAVING A CENTER OF GRAVITY, A PORTION OF SAID ARMATURE MEMBER BEING MOUNTED IN SAID CAVITY FOR MOVEMENT ABOUT A PIVOT AXIS TRANSVERSE OF THE AXIS OF SAID COIL AND PASSING THROUGH SAID CENTER OF GRAVITY, AND A TERMINAL PORTION OF SAID ARMATURE MEMBER PROJECTING OUTWARD FROM SAID CAVITY; (C) SUBSTANTIALLY U-SHAPED MAGNETIC YOKE MEANS; AND (D) TWO POLE PIECES ON SAID YOKE MEANS OPPOSITELY SPACED FROM THE AXIS OF SAID COIL IN A SYMMETRICAL ARRANGEMENT RELATIVE TO SAID LAST-MENTIONED AXIS, SAID TERMINAL PORTION BEING ARRANGED BETWEEN SAID POLE PIECES FOR MOVEMENT ABOUT SAID PIVOT AXIS BETWEEN TWO POSITIONS RESPECTIVELY CLOSELY ADJACENT SAID POLE PIECES. 